JPS6018230B2 - How to clean a turbidity meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cleaning a turbidity meter, and particularly to a cleaning method for a turbidity meter that effectively removes dirt from the inner wall of the turbidity meter by dissolving ozone in cleaning water. It is about the method.

Turbidity meters are used for automatic monitoring of environmental water quality in rivers, etc., and automatic measurement of water quality in water supply, sewage, and industrial wastewater treatment facilities.

The measurement method of the turbidity meter is the surface scattered light measurement method, which measures the scattered light on the surface where the sample water overflows, and the water test tank is equipped with a pair of glass windows, and the light that passes through the sample water is measured through these windows. There are transmitted light measurement methods, etc. In turbidity meters that use the surface scattered light measurement method, errors in indications have occurred over time due to continuous and automated turbidity measurements.

The cause of this was found to be due to dirt on the inner wall of the water test tank, which reduced the effectiveness of the black film provided on the inner wall of the water test tank to prevent light from scattering, resulting in unnecessary scattering. . '1) If dirt is removed from the inner wall of the water test tank, the error will be almost eliminated.

'21 When the inner wall of the water test tank was colored and its influence investigated, it was found that, as shown in the table below, there were large errors in the instructions depending on the coloring of the inner wall of the water test tank, although there were differences in degree.

The coloring was from reddish brown to gray, and these colors were chosen as they were close to the actual color of the dirt. In addition, in the case of a turbidity meter using the transmitted light measurement method, the glass window in contact with the sample water was dirty, and as with the surface scattered light measurement method, large errors occurred in the measured values.

Dirt also adhered to the sample water piping leading to the water test tank, causing problems such as a decrease in the amount of sample water flowing into the water test tank and clogging. The dirt that caused the problem was mainly an organic dirt called slime, and the particular problem with slime was the adhesion of microorganisms and sticky substances discharged by microorganisms.

Slime has a strong adhesive force and cannot be removed by increasing the flow rate of the sample water, so cleaning with a brush or the like is required, but turbidimeters are generally made of dirt that cannot be easily cleaned. It has been found that oxidation using ozone has a remarkable effect as a method for removing this slime. The effect of ozone on slime removal will be explained with reference to FIGS. 1 and 2.
Figure 1 shows an example of the time required to remove slime when a solution containing dissolved ozone is poured into a tube with slime attached. It can be seen from FIG. 1 that the slime is peeled off after being in contact with ozonated water for about 15 to 30 minutes. FIG. 2 shows an example of the effect of flowing ozonated water when a pipe is clogged or a significant decrease in flow rate occurs due to slime adhesion, where the horizontal axis is the period and the vertical axis is the flow rate. However, this is an example where ozonated water is run once every two days. From FIG. 2, it can be seen that by cleaning with ozonated water, a nearly constant flow rate of sample water can be obtained. The purpose of the present invention is to supply cleaning water in which ozone is dissolved instead of sample water to a water test tank in which slime has adhered to the sample water to peel off and remove the slime, thereby making it possible to accurately read the readings from the turbidity meter. An object of the present invention is to provide a method for cleaning and maintaining a turbidity meter.

Embodiments of the present invention shown in the drawings will be described below.

FIG. 3 shows an embodiment of the present invention in which a turbidity meter of the surface scattered light measurement type is used. A water test tank 2 is provided inside the detector 1, sample water flows into the water test tank 2 through a pipe 3, and overflowing sample water is discharged through a drain pipe 4. A light-receiving cell 6 is provided at the upper part of the water test tank 2 to detect the light that is emitted from the light source 5 onto the overflowing surface of the sample water in the water test tank 2 and is scattered depending on the turbidity. Head tank 1 that also serves as a defoaming tank
Sample water sampled by a pump (not shown) is sent to pipe 7.
, an on-off valve 8 , and a cleaning water tank 1 that is supplied with water through a pipe 9
Clean water, which serves as cleaning water, is supplied into the interior of the pipe 1 from a pipe 12.

Ozone generated by the ozone generator 13 passes through a pipe 14 and is diffused into the wash water tank 11 by an aeration device 15 .
Wash water in the wash water tank 11 is sent to the head tank 10 via a pipe 16, an on-off valve 17, and a pipe 18. During measurement, the on-off valve 17 is closed, the on-off valve 8 is opened, and sample water is sent to the head tank 10'.

The sample water that flows down from the head tank 10 through the pipe 3 into the water test tank 2 overflows from the overflowing surface of the water test tank 2 and is discharged to the outside of the apparatus through the drain pipe 4. During cleaning, the on-off valve 8 is closed to stop the supply of sample water to the head tank 10, and fresh water serving as cleaning water is allowed to flow into the cleaning water tank.

During this diving, ozone generated by the ozone generator 13 is diffused to create ozone cleaning water. The on-off valve 17 is opened, and the ozone cleaning water is sent to the head tank 10 through the pipe 18, passes through the test tank 2 in the same manner as the flow of sample water during measurement, and is drained. At this time, the ozone concentration of the ozone cleaning water and the cleaning time are determined by the state of slime adhesion and the cleaning interval. Head tank 1 during measurement by flowing ozone cleaning water.
0. Water test tank 2, slime attached to piping can be peeled off and discharged.

In the above embodiment, the ozone cleaning water was created using the cleaning water tank 11, but when measuring sample water with relatively low turbidity such as rivers and waterworks, the pipe 14 and the aeration device 15 are inserted into the head tank 0' to remove ozone. It is also possible to create cleaning water, omit the cleaning water tank 11, and use the head tank 10 to serve as this.

Furthermore, although the ozone generator 13, head tank 10, wash water tank 11, and detector 1 are shown separately, they can also be integrated into a device.

Furthermore, if the purpose is only to remove slime from the water test tank 2, the pipe 18 can be connected to the water test tank 2 for cleaning. Fourth
The figure shows a structural diagram of a turbidity meter detector using a transmitted light measurement method, and the same reference numerals as in FIG. 3 indicate the same parts.

The transmitted light measurement type turbidimeter detector 21 measures the amount of light emitted from the light source 21a that passes through the sample water through the glass window 21b using the light receiving cell 21c. By flowing ozone cleaning water during cleaning, slime adhering to the glass window can be peeled off, and the same effects as in the case of FIG. 3 can be expected. As explained above, according to the present invention, the slime that adheres to the head tank, water test tank, and piping during measurement with a turbidity meter is removed by flowing cleaning water in which ozone, which has a strong oxidizing power, is dissolved. It is possible to obtain a cleaning method for a turbidity meter that constantly keeps the head tank, water test tank, and piping clean, and also keeps the flow rate of sample water constant, thereby accurately maintaining the measured value of the turbidity meter.

[Brief explanation of drawings]

Fig. 1 is a characteristic diagram showing an example of the effect of ozonated water on removing slime, Fig. 2 is a characteristic diagram showing an example of the effect of ozonated water cleaning on preventing clogging of pipes, and Fig. 3 is a characteristic diagram showing an example of the effect of ozonated water cleaning on preventing clogging of pipes. Fig. 4 is a system diagram showing an embodiment of the present invention applied to a turbidity meter using the transmitted light measurement method. 1...detector, 2...water test tank, 5...
・...Light source, 6... Light receiving cell, 10...
Head tank, 11...Washing water tank, 13.
... Ozone generator, 15 ... Diffusion device, 8, 17 ... Opening/closing valve, 3, 4, 7, 9, 12
, 14, 16, 18... tube, 21...
Transmitted light measurement type turbidity meter, 21a...Light source, 21
b...Glass window, 21c...Light receiving cell. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A turbidity measurement method characterized by supplying cleaning water in which ozone is dissolved instead of sample water into a water test tank for turbidity measurement, and bringing it into contact with slime that has formed in the test tank to peel off the slime. How to clean the meter.